Circular RNAs (circRNAs) are a novel class of non-coding RNAs that are an abundant component of the epitranscriptome. Putative functions of circRNAs, include miRNA sequestration, RNA-binding protein scaffolding, mRNA trapping, and protein translation regulation. Deregulation in one or more of these roles has been linked to several types of cancer, including pancreatic cancer, basal cell carcinoma, and gliomas. One well-studied circRNA, ciRS-7, is believed to act as a miRNA-7 sponge and inhibit its regulation of oncogenic receptors and tumor suppressor factors. Despite all the excitement around circRNAs, many of the recently discovered circRNAs remain poorly understood and progress has been extremely slow. An important reason is the lack of easy-to-use tools to study individual circRNA. Recognizing this unmet need, we propose to develop a simple fluorogenic assay platform to detect circRNAs of interest in biochemical and cell lysate-based samples. In phase I, we will develop a circRNA sensor assay that will specifically recognize ciRS-7 and emit fluorescence signal. Due to portable nature of the proposed assay platform, the ciRS-7 sensor can be easily modified to recognize other circRNAs of interest. Once developed, the circRNA sensor platform would find applications in circRNA research, drug discovery, and biomarker diagnostics.